Optimizing tree spacing and nutrient management for marigold cultivation under Mangifera indica-based agroforestry system in submontane low hill zone of the North-Western Himalaya

Mango (Mangifera indica L.) and marigold (Tagetes erecta L.) stand as significant tree and horticultural crops in the Indian state of Himachal Pradesh’s subtropical zone. Despite their importance, their potential within agroforestry systems remains largely unexplored. The aim was to assess the impact of tree spacing and nutrient levels on a marigold under Mangifera indica cv. Amarpali based agroforestry system at three different spacing i.e. S₁- 2 m × 2 m, S₂- 2.5 m × 2.5 m and, S₃- 3 m × 3 m. The results indicated that mango plants achieved their maximum height, diameter, fruit yield, and fruit size when spaced at S₃- 3 m × 3 m intervals. Likewise, Marigold demonstrated optimal growth and flower production parameters under 3 m × 3 m spacing, whereas these parameters were hindered under closer spacing conditions. The application of Farm Yard Manure (FYM) and nitrogen also demonstrated a significant impact on the development of flower production. Among the various nutrient doses, the combination of T₇-FYM at 60 t ha⁻¹ and Nitrogen at 300 kg ha⁻¹ was considered optimum for marigold cultivation. However, soil chemical properties and nutrient availability reached their highest levels in the closely spaced tree configuration (2 m × 2 m). Additionally, as the distance increased, the soil gradually shifted from acidic to slightly basic. This improvement in soil quality, along with increased marigold yield, suggested that integrating marigold with mango trees could offer a feasible opportunity aimed for farmers in the subtropical regions of Himachal Pradesh to enhance their socioeconomic status.